A laser-diode pumped actively Q-switched Tm,Ho∶YLF laser is reported. The rate equation of Tm,Ho∶YLF Q-switched laser is given including the energy transfer upconversion effect and the analytical expression of initial number of reversion particles is obtained. The influence of energy transfer upconversion effect on the number of upper level reversion particles is analyzed. At room temperature, 2 μm wavelength pulse output is realized. Average output power, single pulse energy and pulse width are measured at different pump power and different repetition rates. The average output power of 189 mW and a optical-optical efficiency of 6.8% are obtained at the repetition rate of 9 kHz and the pump power of 2.8 W. The maximum single pulse energy of 65 μJ and peak power of 0.17 kW are obtained at the repetition rate of 1 kHz.